Washington - The good news? Nobody has to pretend anymore that Gen. Stanley McChrystal knew how to fix Afghanistan within a year. The bad news? Now we're supposed to pretend that Gen. David Petraeus does.

President Obama was absolutely right to sack the preening McChrystal, whose inner circle, as portrayed in Rolling Stone magazine, had all the seriousness and decorum of a frat house keg party. And it was a brilliant political move to turn to Petraeus, who is made of purest Teflon. Critics who might have been tempted to blast the president for changing horses in midstream can hardly object when he has given the reins to the man who averted a humiliating U.S. defeat in Iraq.

Note, however, that I didn't credit Petraeus with "winning" in Iraq. He didn't. What he managed to do was redeem the situation to the point where the United States could begin bringing home its combat troops. If the Obama administration's aims in Afghanistan are recalibrated to accommodate objective reality, then Petraeus can succeed there, too. But this means that the general's assignment should be a narrow one: Lay the groundwork for a U.S. withdrawal to begin next summer, as Obama has pledged.

After relieving McChrystal of his command Wednesday, Obama called in his national security team and read the riot act. No more bickering, sniping, backbiting or name-calling, the president ordered. Play nice.

But all the comity in the world doesn't resolve the essential tension between those who believe our goal in Afghanistan should be defined as "victory" and those who believe it should be defined as "finding the exit." Two thousand years of history are on the side of the "exit" camp, and the fact is that at some point we're going to leave. The question is how much time will pass -- and how many more young Americans will be killed or wounded -- before that inevitable day comes.

McChrystal, who designed the counterinsurgency strategy being attempted in Afghanistan, didn't disguise his opposition to administration officials such as Vice President Biden, Ambassador Karl Eikenberry and special envoy Richard Holbrooke, who questioned whether the strategy could work. Petraeus is far too good a politician to fall into that trap. He won't allow any daylight between himself and the civilian leadership.

But ultimately, there's going to be no way to avoid the central question: What kind of Afghanistan will we leave behind?

One answer would be that we have to leave in place a durable, functional central government that has full legitimacy and control within the nation's borders. This would provide the United States with a reliable ally in a dangerous region, and also ensure that Afghanistan would never again be used as a launching pad for attacks by al-Qaeda. But to get the country to that point, given where it is now, could take a decade or more of sustained, concentrated attention. It would mean not just defeating the Taliban but molding the regime of Afghan president Hamid Karzai into a reasonably honest, effective government. This would be a tall order even if Karzai were a stable, consistent, loyal partner. Does anybody believe that's what he is?

A better answer would be that it's enough to leave behind an Afghanistan that no longer poses a serious threat to the United States or its vital interests. Nation-building would be the Afghans' problem, not ours.

Petraeus was successful in Iraq because he realized that he couldn't create an Athenian democracy in Baghdad. But the highly imperfect Iraqi government is light-years beyond what the general is likely to be able to achieve in Kabul. Even after the war, Iraq was left with modern infrastructure, a highly educated and sophisticated population, and a sizable percentage of the world's proven oil reserves. Afghanistan has none of these advantages. The political culture is stubbornly medieval; the populace is poor, uneducated and wary of foreign influences. Afghanistan does have great mineral wealth, apparently, but no mining industry to dig it out and no railroads to get it to the marketplace.

In recent testimony before Congress, Petraeus was less than definitive when asked about Obama's July 2011 deadline. Because he has such credibility and standing in Washington, his view on when we can begin to leave Afghanistan will be more important than McChrystal's ever was. I hope that by putting Petraeus in charge of the war, President Obama hasn't consigned us to a longer stay. His comments Thursday seem to indicate this possibility.

Eugene Robinson's e-mail address is eugenerobinson(at)washpost.com.

(c) 2010, Washington Post Writers Group 

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